OK, I reread a bunch of this series, and I’d like to refocus my comments. Basically, I’m going to rewrite/expand bits and pieces of Vincent’s points, and then check to make sure I haven’t broken something.

I like the approach (mentioned by a commenter, I think) of turning position a bit inside-out - that is (in my words): game rules and past game play create a large set of constraints upon and opportunities for ongoing game play. A player’s current position is given by those constraints and opportunities. Positioning [italics as per Vincent] refers to the various factors and processes, including in-fiction, cue-mediated, and interpersonal, that determine [my change] those constraints and opportunities.

To keep consistent with Vincent’s usage, I’ll add that player moves consistent with their current constraints and opportunities can be called legitimate moves.

In an RPG, the fiction is constantly created and re-created by the agreement of the group as a whole. As such, it’s possible to alter the understanding of the entire fictional past, present and future at any time in play. That means that it is possible to add, after a move has been attempted, a fictional constraint that makes the move in some way inapplicable, or illegitimate.

Vincent: Have I done any damage to your principles here, or simply reworded it in a way that bothers me less?

Aside: Why does this bother me less? Well, three things come to mind: 1) A somewhat direct definition of legitimate; 2) A clear “added constraint, therefore now illegitimate” step, and 3) More “room” for noticing that design and play-style can enhance - though admittedly not ensure - understanding of what is and isn’t likely to be legitimate. Or reduce problems that might arise from unknown legitimacy (because really, unknown legitimacy is NOT always bad!)

(BTW, for anyone following along (ha!): my Mirror Mage example from other threads? Add to the fiction another Mage capable, say, of the move “block any move involving transport.” If there’s been nothing establishing that such a mage could reasonably exist and be present, you may have an argument that potentially escalates to chair-sliding and door-slamming, but - its’ roots remain fictional, not directly interpersonal. “Directly interpersonal” was the claim I was making earlier, I think, but now I guess I’d see that as vanishingly rare, given the huge range of creativity applicable via retroactive introduction of a constraint. Or maybe you could argue that the move remains legitimate, it’s just that the outcome is pre-empted, but that’s near enough semantics to my eye that I’m not inclined to quibble. Not that I’m opposed to a stronger delineation of legitimacy vs. effectiveness/outcome…)